There are different approaches to implement brokered messaging communication between services using Service Bus Queues (Topics):
CloudFX Messaging
QueueClient
WCF integrated approach
Which of those approaches are more useful in which cases?
Any comparison of performance, abstraction level, testability, flexibility or facilities would be great.
OK, now that I understand your question better, I see where the confusion is.
All 3 of the options that you are looking into are written by Microsoft.
Also, all 3 of those options are simply an abstraction - a client interface into the service that MS is providing.
None of them are faster, slower, etc. However, I would say that if you went the WCF route, then you can more easily abstract the technology choice a bit better.
What I mean by that is - you can develop a "GetMessage" contract in WCF that points to the service bus... and then later on change the design, and configure WCF to point to some other service and you wouldn't have to change the code.
So, that's one advantage for WCF.
That being said, CloudFX is built by Microsoft to give extra common functionality around the usage of the Azure Service Bus ... so don't ignore that. Look into the benefits of that API and decide if you and your team need those features.
Lastly, QueueClient is simply what CloudFX improves on, but adds no benefits like WCF. So you probably don't want to go with this route (considering your other 2 options).
Keep in mind that Azure uses a REST API under the hood for most of the communication... and so you might hit some unexpected performance issues if you don't configure your application correctly: http://tk.azurewebsites.net/2012/12/10/greatly-increase-the-performance-of-azure-storage-cloudblobclient/
I am planning to build a web service for providing JSON/XML data to client via HTTP. And I am planning to make it RESTful, but this is only a best-to-have option rather than a must. And normally, I will host it in IIS.
To achieve this, by my analysis, I have 3 options (I need to use MS technologies): WCF service, WCF Data Service and MVC4 WebAPI. I still have one more question before making the final decision. Yes, there are a lot discussions on web talking when to choose one of them, but they focus on other topics such as Protocol, easy to implement, leverage HTTP etc etc.
However, my focus is on the other aspect: from performance aspect, what is the best one (suppose I correctly use them) from the 3 options (to provide JSON/XML via HTTP)?
Frankly there is no definitive answer to your question, it all depends on what kind of traffic are you expecting (or wanting to serve), what kind of functionality would your REST api have (which also impacts performance), and lots more.
Rick Stahl has created a nice blogpost about this. http://www.west-wind.com/weblog/posts/2012/Sep/04/ASPNET-Frameworks-and-Raw-Throughput-Performance
Its not the final answer to your question (namely what is the best). But it should give you some better perspective and hopefully a better position to answer your question.
I have a question. I would like to serve a series of services made with WCF. The client that consumes the services is also .NET with WCF. I would like to have high speed of access, fast response, transport medium to small Data Contracts (primary .net basic data types). The distribution will be over internet, I´m looking for reliability, availability and basic security.
I don´t want to use WsHttp, because my only client is based on .net and I will have almost 150 clients requesting the services.
What do you suggest to use for binding? Are there any disadvantages, risks, etc?
Thanks in advance!
Since you plan to use simple types and small data contracts, the binding you use is nearly irrelevant compared to the latency introduced by going over the Internet. So, the right answer is to use the one which is easiest to manage and the most secure.
I recommend that you host the app in IIS and use a wsHttpBinding and take all the manageability goodness that goes along with it. It will also happen to be interoperable, and while that is irrelevant today, it is just free, so why not?
And, please consider the granularity of your service. You know your customers better, but on the wide open Internet, stuff happens. Because the round trip time over the Internet is variable and impossible to control, it could take milliseconds or seconds or may not get there at all. So, you should take fewer trips with larger payloads if possible, and use all sorts of caching and async operations to make the app appear "fast".
There is a good article on choosing a binding by Juval Lowy here:
http://www.code-magazine.com/article.aspx?quickid=0605051&page=3
Generally the advice is not to use net tcp binding over the internet. Have not heard of anyone doing it. Although it may work if the ports are open all the way and no one blocks the calls.
Test it with nettcp, if it does not work you just need to change the configuration.
The most important thing is to consider your security needs. Do you just need point to point, then basichttp over ssl. Do you need end to end, then wshttp with message encryption.
According to your scenario, NetTcpBinding is the binding of choice. As you are sure that client will be WCF, no need for interoperability.
Have a look here in Programing WCF Services book.
The only thing I'm not sure about is firewalls. If you have to get trough on of theses, maybe some WS binding could be more appropriate.
I'm just about getting into WCF; but from what I've read so far, like the sample scenarios I found on MSDN and some other sites, I can do all that with web services and applications that call those web services. So why the need for an elaborate layer like WCF?
Most of the comparisons I've googled for explain it more from a programming point of view. Still trying to find answers without much success as to when it makes business and of course programming sense to use the WCF layer as opposed to traditional application to web services model.
Anyone here with experience on both and can advice on how to go about choosing either web services or going the WCF way? What are those things that can't absolutely be done using just plain old web services called by applications and where the WCF layer will save the day.
You've fallen for the Microsoft trap of "it's just about web services" :-)
It's actually a lot more:
it's about service-oriented programming in general (not just web services - you can also write TCP/IP based services, MSMQ queue-based messaging and a lot more)
it's about unifying all the diverse programming models that existed so far (ASMX, Enterprise Services, DCOM, .NET remoting)
it's about providing a lot of ready-made and ready-to-use plumbing which can handle things like reliable messaging, transaction support, security in any shape or form you'd like, service discovery, and a lot more
it's about separating the service implementation from the details of how clients will call it and making this a configurable stack of protocols, encodings etc.
Sure - most of this stuff can be done in ASMX, or .NET remoting - but try to convert an ASMX web service to be callable in your intranet using TCP/IP and transport security... Many of those "older" technologies have a very intricate and direct link to how they're being used - you can't easily change that without changing the whole service code.
WCF separates all these "plumbing details" like what endpoint to call, what protocol to use to call it, how to handle security etc. out into a "WCF stack" that's configurable and composable, so you can easily switch your service XYZ to use HTTP allowing anonymous users to call it, to using TCP/IP with Windows credentials required - your service code won't change a bit - it's only configuration of the plumbing.
That to me is the most compelling reason for WCF - I can totally concentrate on my actual service code, and not pollute it with lots of plumbing stuff - how to handle transports and text encodings and all that. And I can easily change that and adapt to new requirements and needs in deployment without having to touch my actual service code.
Plus, the second major point is extensibility - most of the older technologies just had their one, set way of doing things and many didn't lend themselves to being extended. You had to either adapt to use it the way they did it - or forget about it. WCF has a vast and very intricate system for extending just about anything - you can create your own transport protocol (people have created UDP or SMTP based bindings), you can create your own message encoders (like I had to do to talk to a web service which could only understand ISO-8859-1 encoded messages), and you can extend just about anything else in WCF - all in an organized, well-documented, very stable and safe way.
So these two things - separating out plumbing into configurable layers, and extensibility to the maximum - are the most compelling reasons for me to use WCF.
Edit: Kobi's link above, is a far better answer than mine.
WCF is basically a better architecture for supporting communications. It breaks many dependencies such as hosting (not iis dependent), transport, security, addressing into plugin components, and allows customisation to a very high degree.
Yes you can do a lot with traditional technologies, however you can do more with WCF. If you don't need the features now then of course you can can continue with legacy technologies, however if you prefer you can opt for a better architecture now with an eye on the future but it comes at a cost of having to switch technologies now.
Take this example. If you have a legacy asmx web service, how easily can you offer the same service via an MSMQed endpoint? With WCF its as simple as adding new config settings.
I assume that you are not asking "why not just stick with SOAP/HTTP". WSF allows you to choose a number of different transports rather than just simple HTTP, but as you observe the WS-* technologies allow you to do all that. So I think you're asking why use a powerful but complex framework when the raw technolgies are not impossibly complex?
You could ask this same question of any Framework. You could just use the basic technologies and avoid the learning curve of adopting the framework.
Frameworks such as WCF do have a learning curve, but consider what happens if you don't use them:
You find that you write boiler-plate code for each service invocation. You then either accept duplication or begin to refactor and build your own libraries. Before long you've developed your own Framework, but it's not the same as anybody else's. So then any new team memeber has to learn your local framework, serious learning currve.
Note also that WCF addresses issues such as the monitoring of the deployed solution.
The biggest appeal to me is testability. Services are defined by a CLR interface, which is quite easy to mock inside a test harness. Some words of warning, however. With great flexibility comes some pain in the configuration process, along with a few "gotchas". An example of a gotcha is that WCF--adhering closely to a "best practice"--requires an active SSL connection in order to pass SOAP authentication credentials over HTTP. This hinders testing quite a bit.
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I understand the value of the three-part service/host/client model offered by WCF. But is it just me or does it seem like WCF took something pretty direct and straightforward (the ASMX model) and made a mess out of it?
Is there an alternative to using SvcUtil's command line step back in time to generate the proxy? With ASMX services a test harness was automatically provided; is there a good alternative today with WCF?
I appreciate that the WS* stuff is more tightly integrated with WCF and hope to find some payoff for WCF there, but geeze, otherwise I'm perplexed.
Also, the state of books available for WCF is abysmal at best. Juval Lowy, a superb author, has written a good O'Reilly reference book "Programming WCF Services" but it doesn't do that much (for me anyway) for learning now to use WCF. That book's precursor (and a little better organized, but not much, as a tutorial) is Michele Leroux Bustamante's Learning WCF. It has good spots but is outdated in place and its corresponding Web site is gone.
Do you have good WCF learning references besides just continuing to Google the bejebus out of things?
Okay, here we go. First, Michele Leroux Bustamante's book has been updated for VS2008. The website for the book is not gone. It's up right now, and it has tons of great WCF info. On that website she provides updated code compatible with VS2008 for all the examples in her book. If you order from Amazon, you will get the reprint which is updated.
WCF is not only a replacement for ASMX. Sure it can (and does quite well) replace ASMX, but the real benefit is that it allows your services to be self-hosted. Most of the functionality from WSE has been baked in from the start. The framework is highly configurable, and the ability to serve multiple endpoints over multiple protocols is amazing, IMO.
While you can still generate proxy classes from the "Add Service Reference" option, it's not necessary. All you really have to do is copy your ServiceContract interface and tell your code where to find the endpoint for the service, and that's it. You can call methods from the service with very little code. Using this method, you have complete control over the implementation. Regardless of the method you choose to generate a proxy class, Michele shows both and uses both in her excellent series of webcasts on the subject.
Michele has tons of great material out there, and I recommend you check out her website(s). Here's some links that were incredibly helpful for me as I was learning WCF. I hope that you'll come to realize how strong WCF really is, and how easy it is to implement. The learning curve is a little bit steep, but the rewards for your time investment are well worth it:
Michele's webcasts: http://www.dasblonde.net/2007/06/24/WCFWebcastSeries.aspx
Michele's book website (alive and updated for VS2008): http://www.thatindigogirl.com/
I recommend you watch at least 1 of Michele's webcasts. She is a very effective presenter, and she's obviously incredibly knowledgeable when it comes to WCF. She does a great job of demystifying the inner workings of WCF from the ground up.
I typically use Google to find my WCF answers and commonly find myself on the following blogs:
Blogs with valuable WCF articles
http://blogs.msdn.com/drnick/default.aspx
http://blogs.msdn.com/wenlong/default.aspx
http://blogs.thinktecture.com/buddhike/
http://www.dasblonde.net/default.aspx
Other valuable articles I've found
http://blogs.conchango.com/pauloreichert/archive/2007/02/22/WCF-Reliable-Sessions-Puzzle.aspx
http://blogs.msdn.com/salvapatuel/archive/2007/04/25/why-using-is-bad-for-your-wcf-service-host.aspx
I'm having a hardtime to see when I should or would use WCF. Why? Because I put productivity and simplicity on top of my list. Why was the ASMX model so succesful, because it worked, and you get it to work fast. And with VS 2005 and .NET 2.0 wsdl.exe was spitting out pretty nice and compliant services.
In real life you should have very few communication protocols in your architecture. This keeps it simple an maintainable. If you need to acces to legacy systems, write specific adapters for them so they can play along in the nice shiny and beautiful SOA world.
WCF is much more powerful than ASMX and it extends it in several ways. ASMX is limited to only HTTP, whereas WCF can use several protocols for its communication (granted, HTTP is still the way most people will use it, at least for services that need to be interoperable). WCF is also easier to extend. At least, it is possible to extend it in ways that ASMX cannot be extended. "Easy" may be stretching it. =)
The added functionality offered by WCF far outweighs the complexity it adds, in my opinion. I also feel that the programming model is easier. DataContracts are much nicer than having to serialize using XML serialization with public properties for everything, for example. It's also much more declarative in nature, which is also nice.
Wait.... did you ever use .NET Remoting, cause thats the real thing its replacing. .NET Remoting is pretty complicated itself. I find WCF easier and better laid out.
I don't see it mentioned often enough, but you can still implement fairly simple services with WCF, very similar to ASMX services. For example:
[ServiceContract]
[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
public class SimpleService
{
[OperationContract]
public string HelloWorld()
{
return "Hello World";
}
}
You still have to register the end point in your web.config, but that's not so bad.
Eliminating the verbosity of the separated data, service, and operation contracts goes a long way toward making WCF more manageable for me.
VS2008 includes the "Add Service Reference" context menu item which will create the proxy for you behind the scenes.
As was mentioned previously, WCF is not intended solely as a replacement for the ASMX web service types, but to provide a consistent, secure and scalable methodology for all interoperable services, whether it is over HTTP, tcp, named pipes or MSMQ transports.
I will confess that I do have other issues with WCF (e.g. re-writing method signatures when exposing a service over basicHTTP - see here, but overall I think it is a definite imrovement
If you're using VS2008 and create a WCF project then you automatically get a test harness when you hit run/debug and you can add a reference without having to use svcutil.
My initial thoughts of WCF were exactly the same! Here are some solutions:
Program your own proxy/client layer utilising generics (see classes ClientBase, Binding). I've found this easy to get working, but hard to perfect.
Use a third party implementation of 1 (SoftwareIsHardwork is my current favourite)
WCF is a replacement for all earlier web service technologies from Microsoft. It also does a lot more than what is traditionally considered as "web services".
WCF "web services" are part of a much broader spectrum of remote communication enabled through WCF. You will get a much higher degree of flexibility and portability doing things in WCF than through traditional ASMX because WCF is designed, from the ground up, to summarize all of the different distributed programming infrastructures offered by Microsoft. An endpoint in WCF can be communicated with just as easily over SOAP/XML as it can over TCP/binary and to change this medium is simply a configuration file mod. In theory, this reduces the amount of new code needed when porting or changing business needs, targets, etc.
ASMX is older than WCF, and anything ASMX can do so can WCF (and more). Basically you can see WCF as trying to logically group together all the different ways of getting two apps to communicate in the world of Microsoft; ASMX was just one of these many ways and so is now grouped under the WCF umbrella of capabilities.
Web Services can be accessed only over HTTP & it works in stateless environment, where WCF is flexible because its services can be hosted in different types of applications. Common scenarios for hosting WCF services are IIS,WAS, Self-hosting, Managed Windows Service.
The major difference is that Web Services Use XmlSerializer. But WCF Uses DataContractSerializer which is better in Performance as compared to XmlSerializer.
In what scenarios must WCF be used
A secure service to process business transactions. A service that
supplies current data to others, such as a traffic report or other
monitoring service. A chat service that allows two people to
communicate or exchange data in real time. A dashboard application
that polls one or more services for data and presents it in a logical
presentation. Exposing a workflow implemented using Windows Workflow
Foundation as a WCF service. A Silverlight application to poll a
service for the latest data feeds.
Features of WCF
Service Orientation
Interoperability
Multiple Message Patterns
Service Metadata
Data Contracts
Security
Multiple Transports and Encodings
Reliable and Queued Messages
Durable Messages
Transactions
AJAX and REST Support
Extensibility
source: main source of text
MSDN? I usually do pretty well with the Library reference itself, and I usually expect to find valuable articles there.
In terms of what it offers, I think the answer is compatibility. The ASMX services were pretty Microsofty. Not to say that they didn't try to be compatible with other consumers; but the model wasn't made to fit much besides ASP.NET web pages and some other custom Microsoft consumers. Whereas WCF, because of its architecture, allows your service to have very open-standard--based endpoints, e.g. REST, JSON, etc. in addition to the usual SOAP. Other people will probably have a much easier time consuming your WCF service than your ASMX one.
(This is all basically inferred from comparative MSDN reading, so someone who knows more should feel free to correct me.)
WCF should not be thought of as a replacement for ASMX. Judging at how it is positioned and how it is being used internally by Microsoft, it is really a fundamental architecture piece that is used for any type of cross-boundary communication.
I believe that WCF really advances ASMX web services implementation in many ways. First of all it provides a very nice layered object model that helps hide the intrinsic complexity of distributed applications.
Secondly you can have more than request-replay messaging patterns, including asynchronous notifications from server to client (impossible with pure HTTP), and thirdly abstracting away the underlying transport protocol from XML messaging and thus elegantly supporting HTTP, HTTPS, TCP and other. Backward compatibility with "1-st generation" web services is also a plus.
WCF uses XML standard as the internal representation format. This could be perceived as advantage or disadvantage, especially with the growing popularity "fat-free alternatives to XML" like JSON.
The difficult things I find with WCF is managing the configurations for clients and servers, and troubleshooting the not so nice faulted state exceptions.
It would be great if anyone had any shortcuts or tips for those.
I find that is a pain; in that I have .NET at both ends, have the same "contract" dlls loaded at both ends etc. But then I have to mess about with a lot of details like "KnownType" attributes.
WCF also defaults to only letting 1 or 2 clients connect to a service until you change lots of configuration. Changing the config from code is not easy, shipping lots of comfig files is not an option, as it is too hard to merge our changes into any changes a customer may have made at the time of an upgrade (also we don't want customers playing with WCF settings!)
.NET remoting tended to just work most of the time.
I think trying to pretend that .NET to .NET object based communications is the same as sending bit so of Text (xml) to an unknown system, was a step too far.
(The few times we have used WCF to talk to a Java system, we found that the XSD that the java system gave out did not match what XML it wanted anyway, so had to hand-code a lot of the XML mappings.)